1. Lec.11,

2. Rh-Blood Group

3. Rh-Blood groups:
The Rh-factor named for the rhesus monkey because it was first studied using the blood of this animal.
Rh-agglutinogens (antigens): there are six common types of Rh-antigens each of which is called Rh-factor. These types are C, D, E, c, d, & e.The type D (Rh)-antigen.

4. anyone who has antigen D on RBC membrane is said to be Rh-positive (Rh+) or D-positive (D+) about 85% of population are Rh+, while persons who does not have antigen D on their RBC is said to be Rh-negative (Rh-) or D- & about 15% are D- (Rh- ). Rh+ is dominant while Rh- is ressive.
Rh-agglutinins: The Rh+ individual has no antibody in their plasma. The Rh- person has also no antibody D in the plasma, but Rh- individual forms the antibody –D when injected with D+ (Rh+) cells. Antibodies against Rh-antigen do not develop unless an Rh- person is exposed to Rh+- blood. This can occur through a transfusion or entrance of fetal blood into the maternal circulation across the placenta.

5. Table: Rh –type, agglutiongen, agglutinin, and % of each Rh -group
Agglutinogen on RBC
Agglutinins in plasma %
Rh+ D - 85
Rh- 15

6. (ABO-system)(Rh-system)
The ABO blood type & the Rh -blood type usually are designated together.
(ABO-system)(Rh-system)
For example a person designated as A positive (A+) is blood group A in the ABO- system and Rh+ in the Rh blood group. This person has antigens A & D on RBC & antibody-B& no antibody-D in the plasma.

7. Rh –Transfusion Reaction
is the reaction between antigen -D in Rh+ blood of donor & antibody D in Rh- blood of recipient.

8. Hemolytic disease of newborn (HDN) or erythroblastosis fetalis:
HDN: is a disease of he fetus & neonate. characterized by agglutination between antigen D in the fetus & antibody D produce by the mother. Fetus may develop hemolytic anemia in two major ways a consequence of developing antibodies.
1. Rh- incompatibility. 2. ABO- incompatibility.

9. HDN due to Rh-incompatibility
Mother Rh- (Rh- Rh - ) father+ (Rh+ Rh-) heterozygous Fetus 50% Rh+ (Rh+ Rh-) A 100% chance of producing an Rh+ fetus if the father is homozygous (Rh+ Rh+). Mother (Rh- Rh-) father (Rh+ Rh+) homozygous Fetus 100% Rh+ Rh+

12. Prevalence of disease:
About 3% of second Rh –positive babies exhibit some signs of HDN; 17% of the third babies exhibit the disease; and the incidence rises progressively with subsequent pregnancies. About 50% of Rh negative individuals are sensitized (develop an anti-Rh titer) by transfusion of Rh+blood.

13. Symptoms of disease
severe jaundice
. odema (hyrops fetalis). 3.Kernicterus due to deposition of bilirubin in the basal ganglia which result in brain damage & mental retardation.
. Splenomegaly(enlargement of spleen )
hepatomegaly (enlargement of liver ).

14. Treatment of HDN
1.Treatment of mother----- anti-D antibodies which is called Rho(D) immune globulin (RhoGAM) within 72 hours during the postpartum period or during pregnancy or immediately after each abortion.

15. 2.Treatment of erythroblastic neonate
exchange transfusion i.e. slowly removing the newborn’s blood & replacing it with Rh—blood to reduces the level of maternal antibody-D.
. 2. Exposure of newborn to fluorescent light to breakdown the large amount of bilirubin

16. B. HDN due to ABO-incompatibility
when a mother of type O blood becomes pregnant & the fetus has type A or B antigens on RBC this may result in anemia known as HDN.